The cloning and sequencing of a cDNA for human ribosomal protein L4 is reported. The corresponding mRNA has a very short 5' untranslated region initiating with a sequence of 12 pyrimidines, characteristic of all vertebrate ribosomal protein mRNAs. The deduced amino acid sequence shows that human ribosomal protein L4 has 425 amino acid residues and a calculated molecular mass of 47,821 Da. Comparison with the homologous counterparts of Xenopus, Drosophila and yeast shows that this protein has a very conserved amino-terminus region and an extremely divergent carboxyl-terminus portion.